Multicellular living organisms and unmodified parts thereof and – Method of introducing a polynucleotide molecule into or... – The polynucleotide alters carbohydrate production in the plant
Patent
1998-02-02
2000-12-19
Fox, David T.
Multicellular living organisms and unmodified parts thereof and
Method of introducing a polynucleotide molecule into or...
The polynucleotide alters carbohydrate production in the plant
800286, 8003172, 435101, 435193, 435419, 435468, 536 236, A01H 500, A01H 506, C12N 1529, C12N 1582
Patent
active
061629669
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to transgenic plants which due to genetically engineered modifications synthesize a modified starch, particularly a starch that possesses modified pastification properties and an increased phosphate content as compared to starch synthesized in wild-type plants. Furthermore, the invention relates to processes for producing said transgenic plants as well as the modified starch isolatable from these plants. The invention also relates to the use of DNA sequences encoding disproportionating enzymes (EC 2.4.1.25) for the production of transgenic plants exhibiting a reduced activity of said enzymes and synthesizing a modified starch.
The polysaccharide starch which represents one of the main storage substances in the plant kingdom, in addition to its use in the food stuff industry is also widely used as regenerative source of raw materials for the production of industrial products. In order to facilitate the use of this raw material in as many areas as possible, it is important to obtain a large variety of substances and to adapt it to the respective demands of the manufacturing industry.
Although starch is made up of a chemically homogeneous basic component, namely the glucose, it does not represent a homogeneous raw material. Rather, it constitutes a highly complex mixture from various types of molecules which differ from each other in their branching degree and in the occurrence of the branchings of the glucose chains. One differentiates particularly between amylose-starch, a basically non-branched polymer made up of .alpha.-1,4-interlinked glucose molecules, and amylopectin-starch which in turn is a mixture of glucose chains with different branching degree. The branching results from .alpha.-1,6-glycosidic interlinkings.
The molecular structure of starch which is mainly determined by the branching degree, the amyloselamylopectin ratio, the average chain length as well as the presence of phosphate groups, is decisive for essential functional properties of the starch or the aqueous solutions thereof. Examples of essential functional properties are solubility, retrogradation behavior, the film forming properties, the viscosity, the color stability, the pastification properties, i.e., binding and adhesive properties, as well as low temperature stability. Also the starch granule size may be important for various uses.
The starch isolated from plants is often adapted to industrial uses by chemical modification, which, as a rule, is time and cost intensive. Therefore it appears to be desirable to find possibilities of synthesizing modified starch, which in its properties already meets the demands of the manufacturing industry, directly in plants and isolating the modified starch from these plants. Conventional means for producing plants synthesizing starch that is modified as compared to that produced in wild-type plants are the classical breeding methods and the generation of mutants. For example, in maize a mutant was generated that synthesizes a starch having modified viscosity properties (U.S. Pat. No. 5,331,108) as well as a maize variety (waxy maize) was established by breeding the starch of which consists by almost 100% of amylopectin (Akasuka and Nelson, J. Biol. Chem. 241 (1966), 2280-2285).
Alternatively, plants synthesizing a starch with modified properties can be produced by genetic engineering. Described are, for example, several cases where potato plants were genetically modified with the aim of modifying the starch synthesized in these plants (e.g., WO 92/11376; WO 92/14827). Although in some cases the production of a modified starch in plants was successful, there is still the need for processes for the production of a starch which is modified as compared to starch synthesized in wild-type plants and which is preferably useful in specific industrial manufacturing processes.
The problem underlying the present invention therefore is to provide plants synthesizing a modified starch which differs in its physical and chemical properties from starc
REFERENCES:
Hart et al. Mol. Gen. Genet. 235: 179-188, 1992.
Mazzolini et al. Plant Mol. Biol. 20: 715-731, 1992.
Evans et al. Biochem. Soc. Trans. 20: 3445, 1992.
Kossmann et al. Progress in Biotechnol. 10: 271-278, 1995.
Muller-Rober, B., and J. Kossmann, "Approaches to Influence Starch Quantity and Starch Quality in Transgenic Plants," Plant, Cell And Environment 17:601-613 (1994).
Takaha, T., et al., "Disproportionating Enzyme (4-.alpha. Glucanotransferase; EC 2.4.1.25) of Potato: Purification, Molecular Cloning, and Potential Role in Starch Metabolism," J. Biol. Chem. 268:1391-1396 (1993).
WPI Database, Section Ch, Week 8839, Derwent Publications Ltd., London, GB; Class D17, AN 88-275344 XP002005944 & JP63202396 A (Ezaki Glico), "Oligosaccharide production--containing N-acetyl glucosamine, glucosamine, mannose, or allose at terminal," Aug. 22, 1988.
Buttcher Volker
Kossmann Jens
Springer Franziska
Fox David T.
Haley, Jr. James F.
Shin Elinor K.
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